title: Seasonal and spatial variation of trace elements and metals in quasi-ultrafine (PM₀.₂₅) particles in the Los Angeles metropolitan area and characterization of their sources.
abstract: Year-long sampling campaign of quasi-ultrafine particles (PM₀.₂₅) was conducted at 10 distinct locations across the Los Angeles south coast air basin and concentrations of trace elements and metals were quantified at each site using high-resolution inductively coupled plasma sector field mass spectrometry. In order to characterize sources of trace elements and metals, principal component analysis (PCA) was applied to the dataset. The major sources were identified as road dust (influenced by vehicular emissions as well as re-suspended soil), vehicular abrasion, residual oil combustion, cadmium sources and metal plating. These sources altogether accounted for approximately 85% of the total variance of quasi-ultrafine elemental content. The concentrations of elements originating from source and urban locations generally displayed a decline as we proceeded from the coast to the inland. Occasional concentration peaks in the rural receptor sites were also observed, driven by the dominant westerly/southwesterly wind transporting the particles to the receptor areas.
authors.affiliation: University of Southern California, Department of Civil and Environmental Engineering, 3620 South Vermont Avenue, Los Angeles, CA 90089, USA.
authors.forename: Arian
authors.initials: A
authors.lastname: Saffari
authors.forename: Nancy
authors.initials: N
authors.lastname: Daher
authors.forename: Martin M
authors.initials: MM
authors.lastname: Shafer
authors.forename: James J
authors.initials: JJ
authors.lastname: Schauer
authors.forename: Constantinos
authors.initials: C
authors.lastname: Sioutas
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000706:statistics & numerical data; D004391:Dust / Q000032:analysis*; D004784:Environmental Monitoring; D015141:Los Angeles; D008670:Metals / Q000032:analysis*; D012621:Seasons; D014131:Trace Elements / Q000032:analysis*; D001335:Vehicle Emissions / Q000032:analysis
chemical_list: D000393:Air Pollutants; D004391:Dust; D008670:Metals; D014131:Trace Elements; D001335:Vehicle Emissions
keywords: Los Angeles Basin; PCA; Quasi-ultrafine; Source characterization; Trace element